Tool holder for punches and the like

ABSTRACT

The holder includes a collar within which a punch is clamped by radially movable jaws. The jaws are shifted radially into clamping engagement with the punch by fluid-operated actuators which extend axially of the collar.

United States Patent 1 Scott 1 Oct. 2, 1973 TOOL HOLDER FOR PUNCHES ANDTHE LIKE [75] Inventor: William B. Scott, Steward, Ill.

[73] Assignee: W. A. Whitney Corp., Rockford, Ill.

[22] Filed: Sept. 29, 1971 [21] Appl. No.: 184,685

[52] US. Cl 83/698, 279/4, 279/89, 90/11 A [51] Int. Cl..... B21d 37/04,B23b 31/06, B23q 3/12 [58] Field of Search 279/4, 5, 89; 83/698; 90/11 A[56] References Cited UNITED STATES PATENTS 2,948,540 8/1960 Garberding279/4 FOREIGN PATENTS OR APPLICATIONS 1,140,795 12/1962 Germany 90/11 A1,552,346 12/1969 Germany 90/11 A Primary ExaminerFrancis S. HusarAttorney-Wolfe, Hubbard, Leydig, Voit and Osann [57] ABSTRACT The holderincludes a collar within which a punch is clamped by radially movablejaws. The jaws are shifted radially into clamping engagement with thepunch by fluid-operated actuators which extend axially of the collar.

7 Claims, 6 Drawing Figures PATENTED 2 75 SHEE? 1 BF 2 BJSZZSA PATENTED2W SHEET 2 BF 2 TOOL HOLDER FOR PUNCHES AND THE LIKE BACKGROUND OF THEINVENTION This invention relates in general to a tool holder and, moreparticularly, to a holder for securing a punch on the end of thereciprocable ram of a punch press.

SUMMARY OF THE INVENTION The general aim of the present invention is toprovide a new and improved tool holder which, when compared with priorholders of the same general type, is more compact in construction whileeffecting precise location of the tool and which, at the same time,requires the application of a smaller amount of clamping force to anchorthe tool in its precise location.

In large, the foregoing is achieved through the provision of a noveltool holder with radially movable jaws which are adapted to be movedbetween clamped and released positions in response to the reciprocationof fluid-operated actuators extending axially of the holder, the jawsbeing operable when clamped to interlock with a shoulder on the tool andto prevent axial movement of the tool.

The invention also resides in the comparatively simple construction ofthe holder and in the unique coaction between the holder and the ram toeffect the delivery of pressure fluid to the fluid-operated actuators.

These and other objects and advantages of the invention will become moreapparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of anew and improved tool holder embodying the novel features of the presentinvention and is taken substantially along the line 1-1 of FIG. 3.

FIG. 2 is a perspective view of an exemplary tool adapted to be usedwith the holder.

FIG. 3 is a bottom view of the holder shown in FIG. 1.

FIG. 4 is a top view of the holder shown in FIG. 1. FIG. 5 is across-section taken substantially along the line 5-5 of FIG. 3 butshowing the jaws of the holder in moved positions.

FIG. 6 is an exploded perspective view of certain parts of the holder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in thedrawings for purposes of illustration, the invention is embodied in aholder 10 for anchoring a tool such as a punch 11 on the lower end ofthe reciprocable ram 13 of a punch press (not shown). The ram is mountedslidably at its upper end in a cylinder (not shown) and is adapted toreciprocate the punch downwardly and upwardly through advance and returnstrokes in response to the admission of pressure fluid alternately intoopposite ends of the cylinder. On its advance stroke, the punch coactswith an underlying die to form a hole in an intervening workpiece, thedie and the workpiece having been omitted from the drawings in order tosimplify the latter.

In this instance, the punch holder 10 comprises a generally cylindricalcollar 14 formed with a centrally located bore 15 extending axially ofthe collar and opening out of the lower end thereof so as to receive thepunch 11. The punch includes an intermediate flange 16 (FIG. 2) whoseupper side abuts the lower end of the collar and also includes an uppershank 17 which is telescoped into the bore 15 with only a very smallamount of clearance so as to prevent radial movement of the punch. Asshown in FIG. 2, the shank is tapered upwardly at 19 with the upper endof the taper being located adjacent a downwardly facing shoulder 20defined by the lower surface of a head or so called gage lead 21 at theupper end of the shank, the gage lead enabling accurate centering of theshank in the bore. The gage lead includes a frusto-conical upper surface23, an intermediate grooved surface 24 and a lower cylindrical surface25 whose diameter is the same as the major diameter of thefrusto-conical surface and whose lower side defines the shoulder 20 atthe upper end of the taper l9. Upward movement of the punch within thecollar is limited by engagement of the upper end of the gate lead withthe top surface of the bore.

In order to locate the punch 11 in the proper angular position in theholder 10, an upwardly projecting pin 26 (FIG. 2) is formed on the upperside of the flange 16 and, when the shank 17 is inserted upwardly intothe bore 15, the pin moves into and seats within one of a pair ofcomplementary slots 27 (FIG. 3) formed in the lower end of the collar14. The collar is oriented angularly relative to the ram 13 by means ofa pin 29 (FIG. 4) which projects upwardly from the upper side of thecollar and which fits into a hole (not shown) in the lower end of theram. To anchor the collar to the ram, four cap screws 30 (FIGS. 1 and 3)are received within angularly spaced and axially extending holes 31 inthe collar and are threaded into the end of the ram. When tightened, thecap screws draw the upper side of the collar tightly against the lowerend of the ram and cause a centrally located and upwardly projectingboss 33 (FIG. 1) on the upper side of the collar to seat within adownwardly opening recess 34 in the lower end of the ram.

In accordance with the present invention, the punch 11 is anchoredsecurely in the collar 14 by radially movable jaws 35 (FIGS. 1 and 3)which are adapted to be forced into clamping engagement with the punchby power actuators 36 extending axially of the collar. By virtue of theradially extending jaws and the axially extending actuators, the punchholder 10 is very compact in construction and, at the same time, thejaws coact with the actuators and engage the punch in such a manner thata clamping force of only relatively small magnitude need be applied tothe jaws in order to securely lock the punch in the collar. I

More specifically, the jaws 35 comprise a pair of diametrically opposed,fl at blocks which are fitted slidably into a slot 37 (FIGS. 1 and 3)extending radially of the lower end portion of the collar 14, the slotextending across the bore 15 and being equal in width to the diameter ofthe bore. At its outer end, each jaw 35 is formed with an integralcrosspiece 39 (FIG. 3) which is received within an enlarged opening 40formed in the outer side of the collar at the outer end of the slot 37.The inner end of each jaw is formed with an arcuately concave clampingface 41 for engaging the taper 19 on the shank 17 of the punch 11. Asshown in FIG. I, each clamping face 41 also is inclined downwardly andoutwardly at an inclination corresponding to that of the taper 19.

When the jaws 35 are forced radially inwardly to their clamped positionsshown in FIG. 1, the clamping faces 41 embrace the taper 19 and theupper edges of the inner ends of the jaws lodge beneath the shoulder 20on the punch to positively prevent the punch from being pulleddownwardly out of the collar 14 when the punch is retracted out of theworkpiece. The force tending to pull the punch downwardly is resistedprimarily by the shear strength of the jaws and thus a clamping force ofonly relatively small magnitude need be applied to the jaws to hold thelatter in their clamped positions and to keep the punch locked tightlyin the collar.

The actuators 36 for moving the jaws 35 to and holding the jaws in theirclamped positions preferably are fluid-operated and herein compriseelongated rods 43 (FIG. 1) which are mounted for up and down sliding inaxially extending holes 44 leading upwardly from the lower side of thecollar 14 and intersecting the outer end portions of the slot 37. Thelower end portion of each rod is fitted slidably in a notch 45 (FIGS. 1and 3) formed in the midportion of the crosspiece 39 of the respectivejaw and is formed with a downwardly and outwardly inclined wedgingsurface 46 (FIG. 1) adapted to engage a complementary surface 47 definedby the innermost wall of the notch. When the rods 43 are shifteddownwardly, engagement of the wedging surfaces 46 with the matingsurfaces 47 cams the jaws radially inwardly to their clamped positionsin locking engagement with the punch 11. As the rods are retractedupwardly, the jaws are returned outwardly to released positions (seeFIG. spaced from the shoulder by coil springs 49 (FIG. 3) telescopedinto holes 50 in the collar 14 and compressed between the bottoms of theholes and the end portions of the crosspieces 39 of the jaws.

In order to move the rods 43 upwardly and downwardly, each rod isconnected at its upper end to a piston 50 (FIG. 1)'which is slidableupwardly and downwardly in a cylinder 51 defined by an axially extendinghole formed in the collar 14 and opening out of the upper side thereof.When pressurized air is admitted into the upper ends of the cylinders,the rods are forced downwardly to shift the jaws 35 radially inwardly totheir clamped positions. When the air is dumped from the cylinders, therods are retracted upwardly by coil springs 53 telescoped over the rodsand compressed be tween the pistons and the bottoms of the cylinders. Itwill be appreciated that the springs 53 could be omitted and that therods could be retracted by introducing pressurized air into the lowerends of the cylinders.

Advantageously, pressurized air for actuating the rods 43 is introducedinto the cylinders 51 by way of the ram 13. As shown in FIG. I, an axialpassage 55 extending along the center of the ram opens out of the lowerend of the ram and communicates at its lower end with a hole 56 in thecenter of the boss 33. At its upper end, the passage 55 communicateswith a source of pressurized air through a suitable valve (not shown).Air is delivered from the passage 55 to the upper ends of the cylindersthrough radially extending slots 57 formed in the boss 33, the slotsopening out of the upper side of the boss and leading from the hole 56to the upper ends of the cylinders. Thus, pressurized air delivered intothe ram 13 through the passage 55 is admitted into the upper ends of thecylinders 51 through the hole 56 and the slots 57. The upper ends of thecylinders 51 and the upper sides of the slots 57 are closed off by thelower end of the ram and, to prevent air from escaping outwardly of thecollar 14, an O-ring 60 (FIG. 1) is seated in the upper side of thecollar and seals the latter to the ram.

From the foregoing, it will be apparent that the present inventionbrings to the art a new and improved punch holder 10 of relativelysimple construction. The radially movable jaws 35 in conjunction withthe axially extending actuators 36 provide for compactness while servingto locate the punch securely and accurately.

I claim as my invention:

1. The combination of a vertically reciprocable ram and a holder for apunch, said holder comprising an upright collar secured at its upper endto the lower end of said ram and having an axially extending boreopening out of its lower end for receiving said punch, angularly spacedjaws projecting into said bore and mounted for in and out radial slidingbetween clamped positions engaging said punch and released positionsspaced outwardly from said punch, springs mounted in said collar andurging said jaws outwardly toward said released positions, angularlyspaced cylinders extending axially of said collar and spaced radiallyoutwardly of said bore, fluid-operated actuators guided in saidcylinders for axial reciprocation and operable when reciprocated tocause movement of said jaws between said positions, said cylindershaving open upper ends opening up wardly out of the upper end of saidcollar and closed off by the lower end of said ram, a passage extendingaxially within said ram and communicating with a pressure source fordelivering pressure fluid into the passage, and angularly spaced slotsextending generally radially across the upper end of said collar andcommunicating between said passage and the upper ends of said cylindersto deliver pressure fluid into the cylinders, said slots openingupwardly out of the upper end of said collar and having their uppersides closed off by the lower end of said ram.

2. The combination defined in claim 1 in which said actuators compriserods guided in said collar for axial reciprocation and engageable withsaid jaws, and pistons connected to said rods and slidably receivedwithin said cylinders.

3. A holder for a tool, said holder comprising a collar having anaxially extending bore opening out of one of its ends for receiving saidtool a slot extending radially through said collar and communicatingwith said bore, angularly spaced and generally T-shaped jaws mounted insaid slot for in and out radial sliding between clamped positions inengagement with said tool and released positions spaced outwardly fromsaid tool, crosspieces formed on the outer ends of said jaws andreceived in the end portions of the slot, springs mounted in said collarand urging said jaws outwardly toward said released positions, therebeing two springs associated with each jaw with each pair of springsbeing compressed between said collar and the end portions of therespective crosspiece, reversible actuators guided in said collar foraxial reciprocation and operable when moved axially in one direction toshift said jaws radially inwardly to said clamped positions, there beinga notch formed in the midportion of each crosspiece between said springsand receiving the respective actuator, the outwardly facing surface ofeach notch defining an inclined wedge surface, and mating surfaces onsaid actuators and engageable with said wedge surfaces to cam said jawsinwardly when said actuators are moved to shift said jaws to saidclamped positions.

4. The combination defined in claim 2 in which inclined wedge surfacesare formed on the outer ends of said jaws, and mating surfaces formed onthe free ends of said rods and engageable with said wedge surfaces tocam said jaws inwardly when said rods are moved to shift said jaws tosaid clamped positions.

5. The combination defined in claim 1 in which said collar is formedwith a radially extending slot slidably receiving said jaws, crosspiecesformed on the outer ends of said jaws and received in end portions ofthe last-mentioned slot, there being two springs associated with eachjaw with each pair of springs being compressed between said collar andthe end portions of the respective crosspiece.

6. The combination defined in claim 5 in which a notch is formed in themidportion of each crosspiece and receives the respective actuator, theoutwardly facing surface of each notch defining an inclined wedgesurface, and mating surfaces on said actuators and engageable with saidwedge surfaces to cam said jaws inwardly when said actuators are movedto shift said jaws to said clamped positions.

7. The combination defined in claim 1 in which said jaws are formed witharcuate clamping faces which are inclined downwardly and outwardly.

1. The combination of a vertically reciprocable ram and a holder for apunch, said holder comprising an upright collar secured at its upper endto the lower end of said ram and having an axially extending boreopening out of its lower end for receiving said punch, angularly spacedjaws projecting into said bore and mounted for in and out radial slidingbetween clamped positions engaging said punch and released positionsspaced outwardly from said punch, springs mounted in said collar andurging said jaws outwardly toward said released positions, angularlyspaced cylinders extending axially of said collar and spaced radiallyoutwardly of said bore, fluid-operated actuators guided in saidcylindeRs for axial reciprocation and operable when reciprocated tocause movement of said jaws between said positions, said cylindershaving open upper ends opening upwardly out of the upper end of saidcollar and closed off by the lower end of said ram, a passage extendingaxially within said ram and communicating with a pressure source fordelivering pressure fluid into the passage, and angularly spaced slotsextending generally radially across the upper end of said collar andcommunicating between said passage and the upper ends of said cylindersto deliver pressure fluid into the cylinders, said slots openingupwardly out of the upper end of said collar and having their uppersides closed off by the lower end of said ram.
 2. The combinationdefined in claim 1 in which said actuators comprise rods guided in saidcollar for axial reciprocation and engageable with said jaws, andpistons connected to said rods and slidably received within saidcylinders.
 3. A holder for a tool, said holder comprising a collarhaving an axially extending bore opening out of one of its ends forreceiving said tool a slot extending radially through said collar andcommunicating with said bore, angularly spaced and generally T-shapedjaws mounted in said slot for in and out radial sliding between clampedpositions in engagement with said tool and released positions spacedoutwardly from said tool, crosspieces formed on the outer ends of saidjaws and received in the end portions of the slot, springs mounted insaid collar and urging said jaws outwardly toward said releasedpositions, there being two springs associated with each jaw with eachpair of springs being compressed between said collar and the endportions of the respective crosspiece, reversible actuators guided insaid collar for axial reciprocation and operable when moved axially inone direction to shift said jaws radially inwardly to said clampedpositions, there being a notch formed in the midportion of eachcrosspiece between said springs and receiving the respective actuator,the outwardly facing surface of each notch defining an inclined wedgesurface, and mating surfaces on said actuators and engageable with saidwedge surfaces to cam said jaws inwardly when said actuators are movedto shift said jaws to said clamped positions.
 4. The combination definedin claim 2 in which inclined wedge surfaces are formed on the outer endsof said jaws, and mating surfaces formed on the free ends of said rodsand engageable with said wedge surfaces to cam said jaws inwardly whensaid rods are moved to shift said jaws to said clamped positions.
 5. Thecombination defined in claim 1 in which said collar is formed with aradially extending slot slidably receiving said jaws, crosspieces formedon the outer ends of said jaws and received in end portions of thelast-mentioned slot, there being two springs associated with each jawwith each pair of springs being compressed between said collar and theend portions of the respective crosspiece.
 6. The combination defined inclaim 5 in which a notch is formed in the midportion of each crosspieceand receives the respective actuator, the outwardly facing surface ofeach notch defining an inclined wedge surface, and mating surfaces onsaid actuators and engageable with said wedge surfaces to cam said jawsinwardly when said actuators are moved to shift said jaws to saidclamped positions.
 7. The combination defined in claim 1 in which saidjaws are formed with arcuate clamping faces which are inclineddownwardly and outwardly.